diff --git a/.github/workflows/check.yml b/.github/workflows/check.yml
index 385d8c5..65e7c68 100644
--- a/.github/workflows/check.yml
+++ b/.github/workflows/check.yml
@@ -12,6 +12,8 @@ permissions:
 jobs:
   flake-check:
     runs-on: ubuntu-latest
+    env:
+      nixpkgs: "https://flakehub.com/f/NixOS/nixpkgs/0.2505.810656"
     steps:
       - uses: actions/checkout@v4
       - uses: DeterminateSystems/determinate-nix-action@main
@@ -19,10 +21,10 @@ jobs:
 
       - name: Check Nix formatting
         run: |
-          nix shell "https://flakehub.com/f/NixOS/nixpkgs/0.2411.715026#nixfmt-rfc-style" --command \
+          nix shell "${{ env.nixpkgs }}#nixfmt-rfc-style" --command \
             sh -c "git ls-files '*.nix' | xargs nixfmt --check"
 
       - name: Check links in README
         run: |
-          nix shell "https://flakehub.com/f/NixOS/nixpkgs/0.2411.715026#lychee" --command \
+          nix shell "${{ env.nixpkgs }}#lychee" --command \
             lychee README.md
diff --git a/flake.nix b/flake.nix
index 4b8e690..29380fe 100644
--- a/flake.nix
+++ b/flake.nix
@@ -335,6 +335,30 @@
             }) output
           );
       };
+
+      htmlDocsSchema = {
+        version = 1;
+        doc = ''
+          The `htmlDocs` flake output defines packages providing static HTML output.
+        '';
+        inventory =
+          output:
+          self.lib.mkChildren (
+            # This requires a special function because this output is structured
+            # htmlDocs.${package}.${system} rather than the usual ${output}.${system}.${package}
+            builtins.mapAttrs (packageName: systemsForPackage: {
+              forSystems = builtins.attrNames systemsForPackage;
+
+              children = builtins.mapAttrs (systemType: drv: {
+                forSystems = [ systemType ];
+                derivation = drv;
+                evalChecks.isDerivation = checkDerivation drv;
+                isFlakeCheck = false;
+                what = "HTML documentation";
+              }) systemsForPackage;
+            }) output
+          );
+      };
     in
 
     {
@@ -359,8 +383,7 @@
                 shortDescription = package.meta.description or "";
                 derivation = package;
                 evalChecks.isDerivation = checkDerivation package;
-                inherit what;
-                isFlakeCheck = isFlakeCheck;
+                inherit isFlakeCheck what;
               }) packagesForSystem;
             }) output
           );
@@ -381,6 +404,7 @@
       schemas.nixosModules = nixosModulesSchema;
       schemas.homeConfigurations = homeConfigurationsSchema;
       schemas.homeModules = homeModulesSchema;
+      schemas.htmlDocs = htmlDocsSchema;
       schemas.darwinConfigurations = darwinConfigurationsSchema;
       schemas.darwinModules = darwinModulesSchema;
       schemas.dockerImages = dockerImagesSchema;